diff --git a/index.js b/index.js
index afa716d..ff11a53 100644
--- a/index.js
+++ b/index.js
@@ -28,12 +28,22 @@ function deleteChatId(from) {
 }
 
 function updateChatId(from, chat_id) {
-    chat_ids[from] = chat_id;
+    chat_ids[from.toLowerCase()] = chat_id;
     logger.verbose('Chat id ' + chat_id + ' ' + from);
 }
 
+function getChatId(partner) {
+    try {
+        return chat_ids[partner.toLowerCase()];
+    }
+    catch(e) {
+        return;
+    }
+
+}
+
 function sendMessage(destination, message) {
-    var chat_id = chat_ids[destination];
+    var chat_id = getChatId(destination);
 
     if (!chat_id) {
         logger.warn('Can not find approriate chat id for ' + destination + '. Abort sending message.');
@@ -53,6 +63,7 @@ bot.on('text', function (msg) {
 	logger.info('Incoming message (' + msg.chat.id + '): ' + msg.text, {message: msg});
 
     var from = msg.from.username.toUpperCase() + config.msisdn_suffix;
+    updateChatId(from, msg.chat.id);
 
 	var now = Math.floor(new Date().getTime()/1000);
 
@@ -64,8 +75,6 @@ bot.on('text', function (msg) {
 		return;
 	}
 
-    updateChatId(from, msg.chat.id);
-
     var greeting_prefix = "Pesan anda telah diterima:";
     if (config.greeting_prefix) {
         greeting_prefix = config.greeting_prefix;